The real Ackman and Icahn—scary

In years gone by, there was a band of staunch, value-oriented gentlemen who scoured Wall Street for valuable relics that were thought to have been lost to antiquity.

These pale-investors prided themselves on finding jewels buried deeply in the stock market, hoping to unearth, and unlock, the value that these once-prized, and now tarnished treasures had to offer.

Adam Jeffery (L) | David Grogan (R) | CNBC

Bill Ackman and Carl Icahn

In the 1980s, they were known as corporate raiders. Names like Steinberg, Edelman, Jacobs, Pickens, Posner and Icahn dominated the headlines of their day. With the unbridled support of the philanthropic, Michael Milken, they used his enormous grants of cash to ply their trade. They raided corporations that were unloved, or undervalued, while promising to "unlock shareholder value" … a noble effort which they claimed would enrich the average investor.

In truth, they levered up cyclical companies, raided their overfunded pension plans and, in many cases, drove companies into bankruptcy after using a company's own cash to engage a multitude of strategies that aided the raider, but pilfered the company's coffers. Corporate CEOs cowered at their very names. They recapitalized, restructured, levered up, or did anything the raiders told them to do in hopes of keeping their own jobs while sending the raiders away with their booty.

In the end, the raiders enriched themselves far more than they did individual investors, and made quite a name for themselves in the process, while plundering many a good company.

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Many accepted generous buyouts from the companies they threatened to take over, a perfectly legal form of corporate extortion known as "greenmail."

Among the first to be labeled a "greenmailer" was none other than Carl Icahn.

They were paid handsomely to sell their stock back to the company, at a premium, if they would just go away, promising never to return. (That was politely called a "standstill agreement.")

When all was said and done, the raiders/greenmailers/financiers enriched themselves at the expense of corporations, and their shareholders, but claimed the high ground by pointing to rising share prices of the companies they targeted. Rarely did the bemoan the immense debt they saddled the companies with, that would eventually, create a crisis in the stock market.

In the aftermath of all those the raids, and the subsequent debt defaults they triggered, that style of investing fell into disrepute, as raiders of the lost art fell on hard times, lost their influence, or went to jail for trading and profiting on inside information. And that was at the end of the "roaring '80s."

During the peak of the plundering, the raiders were often compared to the "robber barons" of the Gilded Age.

However, the "robber barons" actually built America's corporate, and physical, infrastructure while their descendants tore it apart.

Sadly, the raiders are mounting a comeback. Some of them are aging greenmailers of years gone by. Some are new, and some are legitimate "activist" investors who seek to improve the quality of the businesses they target.

One old raider, and one new one, have been making headlines of late. Carl Icahn, rising Phoenix-like from the ashes of the '80s and Bill Ackman, a neo-Cahn, have re-invented the art of the deal, buying even smaller slivers of great American companies, agitating for change and, in some cases, walking away with nifty profits. What they are really doing is simply putting a new spin on the type of financial engineering that was pioneered some three decades ago.

What is most interesting of late is that Icahn and Ackman, recently ended a decade-long feud, which culminated in an epic long/short battle over a dink stock — to use a Gordon Gekko phrase — called Herbalife. Their TV war of words over Herbalife is now the stuff of market lore, and was one of CNBC's must-watch moments. (Watch the clip.)

Published reports say the two have buried the hatchet and may now work together as "activist" investors. Indeed, in a recent interview, Icahn, who once called Ackman a "crybaby in the schoolyard," said: "There is a much greater possibility that we are on the same side than the opposite."

A shudder should run down the spines of all God-fearing CEO's who will now be distracted by these opportunists, who are raiding corporate cash hoard of highly successful corporate icons, instead of the overfunded pensions of failing airlines, oil companies, or other old-line businesses.

Commentary by Ron Insana, a CNBC and MSNBC contributor and the author of four books on Wall Street. He also delivers a daily podcast, "Insana Insights," and a long-form weekly version, both available on iTunes and at roninsana.com. Follow him on Twitter @rinsana.